Mitigating loss of genetic diversity is a major global biodiversity challenge1–4. To meet
recent international commitments to maintain genetic diversity within species5,6,
we need to understand relationships between threats, conservation management
and genetic diversity change. Here we conduct a global analysis of genetic diversity
change via meta-analysis of all available temporal measures of genetic diversity from
more than three decades of research. We show that within-population genetic diversity
is being lost over timescales likely to have been impacted by human activities, and that
some conservation actions may mitigate this loss. Our dataset includes 628 species
(animals, plants, fungi and chromists) across all terrestrial and most marine realms
on Earth. Threats impacted two-thirds of the populations that we analysed, and less
than half of the populations analysed received conservation management. Genetic
diversity loss occurs globally and is a realistic prediction for many species, especially
birds and mammals, in the face of threats such as land use change, disease, abiotic
natural phenomena and harvesting or harassment. Conservation strategies designed
to improve environmental conditions, increase population growth rates and introduce
new individuals (for example, restoring connectivity or performing translocations)
may maintain or even increase genetic diversity. Our findings underscore the urgent
need for active, genetically informed conservation interventions to halt genetic
diversity loss.
